第10回EuroBio 2006　（2006年10月25－27日、パリ）

＜会長からの挨拶＞

アキセル・カーン会長は、EuroBio 2006の開催意義について次のように述べている。

「バイオテク産業は、現在までアメリカが世界をリードしてきている。しかし、アメリカは今、ヨーロッパやアジアのパワーハウスの出現によって、重大な競争に対応しなければなくなってきている。産業界も研究者達も、それがヨーロッパ、アメリカ、アジアのどこで活動していても、真実の成功は共同作業から生まれてくるものです。EuroBiOからスタートする共同作業もその種類のものである。

ヨーロッパはもはや単なる「古い」大陸ではない。我々は、未知のものに対して注意深く前進していく知恵をもっている。ヨーロッパは、新しいバイオテクなど領域に関して既に活発な活動を行っている。これまで、ヨーロッパは、新世代の研究開発に対して十分な信頼を示す点で遅れていたのだと思う。しかし、今、その方策が明確になってきている。重要な点は、革新のための資源がヨーロッパ大陸の全体に分布していることである。これまでの思慮深いヨーロッパは、今、進取的なヨーロッパへと自らを変身させてきている。我々は、我々のパートナーが賞賛するように包括的な倫理的コードを保持しつつ、変化に取り組みつつある。こうした重要な変化を通して、かつてヨーロッパが成し遂げたルネッサンスと同じように、21世紀のバイオ革命の花を咲かせようとしている。EuroBiOは、この野心に対して触媒作用を果たすものとなるであろう。」

＜主な講演＞

●「抗体革命」：Gregory Winter (MRC Laboratory)　

　Antibodies were discovered in 1890 but for nearly 100 years have languished on the periphery of the pharmaceutical industry. Yet just within the last ten years antibodies have suddenly emerged as a powerful mainstream pharmaceutical, a multi-billion market, with over 17 antibodies now approved by the FDA. In 2004, the global market reached $11.2 bn. This revolution required several steps, in particular the invention of monoclonal antibodies, and the advent of recombinant DNA technology and protein engineering. I will provide a perspective on the long march of antibodies to the clinic for the treatment of cancer and immune disorders.

●「微小分子」：Hiroshi Ueda (The University of Tokyo)

　Open Sandwich immunoassay as a general detection principle for low-molecular weight antigens

　　Proteins having multiple epitopes are measurable by sandwich ELISA, which usually permits high sensitivity as well as wide working range. On the contrary, monovalent antigens with less than 1000 in MW are not susceptible of sandwich assays due to their small size, and have almost always been measured by competitive assays. However, due to the principle of ratiometric measurement, optimization of the reaction condition is inevitable to attain suitable sensitivity and working range, which are often inferior than those of sandwich assays.
As an alternative immunoassay for small antigens, we propose a noncompetitive ‘Open Sandwich Immunoassay’, which is based on the principle of stabilization of antibody variable region Fv upon binding with antigen. By ELISA detecting labeled VH fragment bound to immobilized VL in the presence of sample, various small molecules with MW around 200-300 were found to be measured with superior detection limit and working range than those attained with corresponding competitive assays. The results imply a common antigen recognition mode of anti-hapten antibody, and also wide applicability of the assay to the sensitive and handy analysis of low molecular weight substances in the areas such as clinical diagnostics and environmental analyses.

●「疾病や中毒の治療のための免疫薬物療法」：Kim D Janda (The Scripps Research Institute)

Simply defined, immunopharmacotherapy is the development of a vaccine(s) applied to treatment of exposure to drugs of abuse; more specifically this methodology was developed to trigger an arm of the immune system not normally activated so as to sequester either actively or passively (administration of a monoclonal antibody or an antibody displayed on a virus) the small molecule (drug) before it can access its target(s) in the CNS. We have used both active and passive vaccines to treat addictions associated with administration of cocaine, nicotine, amphetamines, THC (marijuana) and most recently obesity and cancer.
Our strategy has been to use immunopharmacotherapy as a way to treat addiction. Significantly, such a therapy would operate outside the purview of the central nervous system and therefore would not be subject to numerous side effects that occur with standard pharmaceutical agents. Our work has engaged aspects of chemistry, immunochemistry, and immunology necessary for the implementation of immunopharmacological protocols aimed at the abatement of different dependences. Thus, we will detail our strategies for the production of both active, passive and vaccines.

●「Fabrication of antibody with affinity for inorganic materials by CDR-grafting technique」：Izumi Kumagai (Tohoku University)

Antibody molecules are naturally occurring recognition devices with high and specific binding ability to target molecules. Recently, the function attracts a growth interest in the bottom-up fabrication procedures of nanoscale devises. Several peptides with affinity for non-biological inorganic materials have been reported, and the functional peptide/proteins with affinity for non-biomaterials are expected to be one of the building block tools for the assembly of nanomaterials. Here, we append the affinity for inorganic material to antibody by replacing the complementarity determining regions (CDRs) of antibody with a specific peptide for the corresponding material. The utilization of the peptide for innovating antibody would open the way to convenient preparation for the antibody against non-biomaterials. Anti hen egg-white lysozyme (HEL) antibody, HyHEl-10 was applied as a scaffold for grafting and the peptide with affinity for zinc oxide (ZnO) was induced into various CDR regions. We would show the possibility that the CDR-grafting technique leads to the innovation of the antibody with affinity for non-biomaterials.

●癌の抗体療法：理論と実際：K. Dane Wittrup (Massachusetts Institute of Technology)

IgG and scFv antibody therapeutics face a series of potential kinetic obstacles in order to reach every cell in a tumor or micrometastasis: too-rapid clearance from circulation; slow extravasation from the vasculature; slow diffusion through the extracellular space; and rapid endocytic consumption. Ratios of characteristic rates of these processes yields two simple quantitative criteria that must be satisfied in order to saturate a volume of tumor tissue with antibody. The Thiele modulus Φ2 is the ratio of characteristic endocytic consumption rate to transport rate, and must be < 1 for saturation. The clearance modulus Γ is the ratio of systemic clearance rate to transport, and must also be < 1 for saturation. In general, Γ < 1 is difficult to satisfy for scFvs, and Φ2 < 1 is difficult to satisfy for IgGs due to a generally under-appreciated limitation in extravasation rates.
We have engineered an scFv against human carcinoembryonic antigen with extremely slow dissociation kinetics (half-time for dissociation ~ 1 week at 37°C). Surprisingly, in a xenograft tumor model, this scFv is cleared from the tumor within 24 hr, similar to an scFv with 1,000-fold faster dissociation kinetics. Fluorescence microscopic studies of cells and spheroids in culture reveal a potential explanation, as surface-bound scFv is endocytosed on the minutes-hours time scale, at a flux of tens to hundreds of thousands of scFv molecules per hour. We have engineered variants of the high affinity scFv with a single PEG chain attached to extend half-life in the bloodstream, and have introduced an inter-domain disulfide bond to stabilize the scFv against proteolysis in tumor tissue. We are performing quantitative studies to follow the penetration of these constructs into tumor spheroids (by confocal microscopy and IHC), and xenografted tumors (by radiolabel biodistribution and IHC).

●Production of Fully Human Polyclonal Antibodies in Cows

James M Robl (Hematech)

●Development of recombinant human polyclonal antibodies against Rhesus-D

John Haurum (Symphogen A/S)

●Display Technologies

Alex Duncan (Cambridge Antibody Technology)

●Fc Engineering

Jeffery V Ravetch (The Rockefeller University)

●Beyond Antibodies

Masayuki Tsuchiya (Chugai Pharmaceutical Co. Ltd.)

●Antibody mimetics derived from small disulfide-rich scaffolds

Willem Pim C Stemmer (Amunix Inc.)

●Nanobodies™ as new therapeutic entities

Hennie R Hoogenboom (Ablynx)

●Infectious Diseases

James D. Marks (University of California, San Francisco)

●Analyses of antibody repertoire against influenza viruses in human bodies

Yoshikazu Kurosawa (Fujita Health University)

●Development of therapeutic Human monoclonal antibodies using KM mice

Shiro Kataoka (Kirin Brewery Co. Ltd.)

●Anti-tumor effects of human monoclonal antibody HMMC-1 on lymph node metastasis of endometrial cancer

Atsushi Suzuki, Daisuke Aoki (Keio University)

●Cancer therapy with antibodies that target the CD28/B7 superfamily of receptor ligand pairs

Nils Lonberg (Medarex)

●Human anti-human IL-18 antibody recognizing the IL-18-binding site 3 with IL-18 signaling blocking activity

Yuji Ito (Kagoshima University)

●Autoimmune Diseases

Norihiro Nishimoto, Tadamitsu Kishimoto (Osaka University)